Metal sleeper surfacing purpose?

[MisterSheeps]

See attached, is an orange corrugated surface plate attached to a metal sleeper amid a long run of concrete sleepers, at Shotton High Level, Wrexham bound line. Why a single metal sleeper, and why the corrugated surface plate?
The Bidston bound line is metal sleepered, no surface plates.

 

[Bald Rick]

See attached, is an orange corrugated surface plate attached to a metal sleeper amid a long run of concrete sleepers, at Shotton High Level, Wrexham bound line. Why a single metal sleeper, and why the corrugated surface plate?
The Bidston bound line is metal sleepered, no surface plates.

it’s a hollow sleeper so that signalling cables etc are routed through it. Which means the cables won’t be damaged when a tamper goes through.

on the adjacent track you can see the same cable(s) routed through orange pipe.

 

[MisterSheeps]

Oh, thank you! ... is a hollow sleeper the new way to do it, and the orange pipe method now obsolete?

 

[Bald Rick]

Oh, thank you! ... is a hollow sleeper the new way to do it, and the orange pipe method now obsolete?

more or less, yes.

 

[pdeaves]

more or less, yes.

where 'new' isn't that new (at least a decade), but of course changes only happen when needed.

 

[Gostav]

Oh, thank you! ... is a hollow sleeper the new way to do it, and the orange pipe method now obsolete?

The use of hollow sleepers means no wires need to be remove or change when the track is being tamped.

 

[Flange Squeal]

Which means the cakes won’t be damaged when a tamper goes through.

That would be a disaster!

 

[Bald Rick]

That would be a disaster!

well, you have to keep the track techs happy.

(corrected, thank you !)

 

[Trestrol]

As the PWay were incapable of spotting orange pipe while tamping.

 

[hwl]

As the PWay were incapable of spotting orange pipe while tamping.

No but it isn't about spotting - this mean they don't have to do anything unlike the orange pipe case, this substancial reduces overall work load

 

[Boodiggy]

As the PWay were incapable of spotting orange pipe while tamping.

Must be S&T with a comment like that!

== Doublepost prevention - post automatically merged: 22 Apr 2023 ==

No but it isn't about spotting - this mean they don't have to do anything unlike the orange pipe case, this substancial reduces overall work load

Hopefully the pway tech gets the operator to amend the tine depth on the tamped though.

 

[Annetts key]

Good tamper operators were perfectly able to avoid hitting orange pipes. Back in the 1980s, soon after orange pipes were introduced to the area where I worked, my team leader (back then known as a senior technician) had a discussion with a tamper operator.

It was generally agreed that using orange pipes was better than black signalling cables just being routed through a bed on its own or being poorly clipped to the top of sleeper (by poorly, I mean the cable drooping as it passed under the rail).

Of course, orange pipes fell out of favour, and now cables are clipped to the tops of the sleepers again. Unless there are lots of them, in which case these hollow metal sleepers are used.

Of course, poor tamper operators were capable of mistakes. Once, a tamper hit the switch rail on the toe of a set of points so badly that they had to be clipped out of use. And that was after the bulge had been ground down so that the switch rail would close up…

But IMHO, ballast regulators were far worse. Also CWR / LWR being dragged along the four foot…

 

[Bald Rick]

As the PWay were incapable of spotting orange pipe while tamping.

the orange pipe was quite deliberate, such that even if the tamper tines did get close to it, it would just spin with the vibrations. However, sometimes, S&T would have a cable coming out of a hole drilled into the pipe, which defeated the object…

 

[Snow1964]

The hollow sleepers will never be as good as a separate cable tunnel below the balast bed where lots of cables need to pass through.

Obviously if the sleeper ever needed replacing, all the cables would need disconnecting, drawn back through, sleeper replaced, need threading through again, run to the reconnection point, reconnecting, and possibly electrically testing.

 

[zwk500]

The hollow sleepers will never be as good as a separate cable tunnel below the balast bed where lots of cables need to pass through.

Obviously if the sleeper ever needed replacing, all the cables would need disconnecting, drawn back through, sleeper replaced, need threading through again, run to the reconnection point, reconnecting, and possibly electrically testing.

Would they? The sleeper in the OP looks like you can unbolt the cover and rail fastenings, allowing you to life the rails slightly, slide the sleeper out (which is presumably U-shaped not with a circular channel that's enclosed) and then put a replacement in and bolt everything back down.
There's a concrete version on this twitter thread: https://twitter.com/networkrailse/status/1249335893489573892 (with a bit of inter-route joking from the Wessex team).

 

[Hellzapoppin]

Hollow bearers should only be used for local cables so in the event of a relay job they’d have to be disconnected anyway. Utxs are expensive to build, they will need confined space access protocols put in place (although that rarely happens) to get in to. They fill with water, which will need pumping out. All in all hollow bearers are the best option although if an existing utx is available and obviously close enough then it should be used first.

 

[Trestrol]

Must be S&T with a comment like that!

== Doublepost prevention - post automatically merged: 22 Apr 2023 ==

Is it that obvious!

 

[hwl]

Would they? The sleeper in the OP looks like you can unbolt the cover and rail fastenings, allowing you to life the rails slightly, slide the sleeper out (which is presumably U-shaped not with a circular channel that's enclosed) and then put a replacement in and bolt everything back down.
There's a concrete version on this twitter thread: https://twitter.com/networkrailse/status/1249335893489573892 (with a bit of inter-route joking from the Wessex team).

Correct and they can easily be retrofitted to replace "orange pipes" with no disconnections.

 

[Elecman]

Hollow bearer sleeper for passing cables through. Only allowed to pass cables carrying 110 volt maximum through orange pipes after a major fire on a Tamper after it went through a 400 volt cable some years ago

 

[Annetts key]

the orange pipe was quite deliberate, such that even if the tamper tines did get close to it, it would just spin with the vibrations. However, sometimes, S&T would have a cable coming out of a hole drilled into the pipe, which defeated the object…

When used for track circuit cables, AWS cables, or ATP cables, this was deliberate design. Plastic clips were supposed to be fitted to prevent the pipe from moving or rotating.

The hollow sleepers will never be as good as a separate cable tunnel below the balast bed where lots of cables need to pass through.

Obviously if the sleeper ever needed replacing, all the cables would need disconnecting, drawn back through, sleeper replaced, need threading through again, run to the reconnection point, reconnecting, and possibly electrically testing.

Under track crossings (UTX) are supposed to be used for all lineside (medium/long distance) cables.
Orange pipes and hollow sleepers are only supposed to be used for tail (short distance) cables that feed equipment in the local vicinity.

Hollow bearers should only be used for local cables so in the event of a relay job they’d have to be disconnected anyway. Utxs are expensive to build, they will need confined space access protocols put in place (although that rarely happens) to get in to. They fill with water, which will need pumping out. All in all hollow bearers are the best option although if an existing utx is available and obviously close enough then it should be used first.

And then there are temporary arrangements, where if the UTX cannot be used (unable to locate it, collapsed, or full), with appropriate authority and authorisation, occasionally a lineside cable may be routed through a hollow sleeper, or orange pipe…

Hollow bearer sleeper for passing cables through. Only allowed to pass cables carrying 110 volt maximum through orange pipes after a major fire on a Tamper after it went through a 400 volt cable some years ago

Tail cables used by S&T should only ever carry 110V AC or 110V/120V DC or lower voltage circuits. I can’t speak for the D&P (E&P), but even BR S&T considered 650V cables that had to cross the railway should be in a UTX or use a bridge or signal gantry.